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Clinical use of CuO nanoparticles (NPs) as antibacterials can be hampered by their toxicity to human cells. We hypothesized that certain surface functionalizations of CuO NPs may render NPs toxic to bacteria, but still be relatively harmless to human cells. To control this hypothesis, the toxicity of differently functionalized CuO NPs to bacteria Escherichia coli vs human cells (THP-1 macrophages and HACAT keratinocytes) was compared using similar conditions and end points. CuO NPs functionalized with polyethylene glycol (CuO-PEG), carboxyl (CuO-COOH, anionic), ammonium (CuO-NH 4 + , cationic) and unfunctionalized CuO NPs and CuSO 4 (controls) were tested. In general, the toxicity of Cu compounds decreased in the following order: CuO-NH 4 + > unfunctionalized CuO > CuSO 4 > CuO-COOH > CuO-PEG. Positively charged unfunctionalized CuO and especially CuO-NH 4 + proved most toxic (24-h EC 50 = 21.7-47 mg/l) and had comparable toxicity to bacterial and mammalian cells. The multivariate analysis revealed that toxicity of these NPs was mostly attributed to their positive zeta potential, small hydrodynamic size, high Cu dissolution, and induction of reactive oxygen species (ROS) and TNF-α. In contrast, CuO-COOH and CuO-PEG NPs had lower toxicity to human cells compared to bacteria despite efficient uptake of these NPs by human cells. In addition, these NPs did not induce TNF-α and ROS. Thus, by varying the NP functionalization and Cu form (soluble salt vs NPs), it was possible to "target" the toxicity of Cu compounds, whereas carboxylation and PEGylation rendered CuO NPs that were more toxic to bacteria than to human cells envisaging their use in medical antibacterial products.

Bacterial infections are one of the leading causes of death worldwide. In the case of topical bacterial infections such as wound infections, silver (Ag) has historically been one of the most widely used antibacterials. However, scientific publications have demonstrated the adverse effects of silver on human cells, ecotoxicity and insufficient antibacterial effect for the complete elimination of bacterial infections. The use of Ag in the form of nanoparticles (NPs, 1–100 nm) allows to control the release of antibacterial Ag ions but is still not sufficient to eliminate infection and avoid cytotoxicity. In this study, we tested the potency of differently functionalized copper oxide (CuO) NPs to enhance the antibacterial properties of Ag NPs. The antibacterial effect of the mixture of CuO NPs (CuO, CuO–NH2 and CuO–COOH NPs) with Ag NPs (uncoated and coated) was studied. CuO and Ag NP combinations were more efficient than Cu or Ag (NPs) alone against a wide range of bacteria, including antibiotic-resistant strains such as gram-negative Escherichia coli and Pseudomonas aeruginosa as well as gram-positive Staphylococcus aureus, Enterococcus faecalis and Streptococcus dysgalactiae. We showed that positively charged CuO NPs enhanced the antibacterial effect of Ag NPs up to 6 times. Notably, compared to the synergy of CuO and Ag NPs, the synergy of respective metal ions was low, suggesting that NP surface is required for the enhanced antibacterial effect. We also studied the mechanisms of synergy and showed that the production of Cu+ ions, faster dissolution of Ag+ from Ag NPs and lower binding of Ag+ by proteins of the incubation media in the presence of Cu2+ were the main mechanisms of the synergy. In summary, CuO and Ag NP combinations allowed increasing the antibacterial effect up to 6 times. Thus, using CuO and Ag NP combinations enables to retain excellent antibacterial effects due to Ag and synergy and enhances beneficial effects, since Cu is a vital microelement for human cells. Thus, we suggest using combinations of Ag and CuO NPs in antibacterial materials, such as wound care products, to increase the antibacterial effect of Ag, improve safety and prevent and cure topical bacterial infections.

Due to the high prevalence of infectious diseases and their concurrent outbreaks, there is a high interest in developing novel materials with antimicrobial properties. Antibacterial and antiviral properties of a range of metal-based nanoparticles (NPs) are a promising means to fight airborne diseases caused by viruses and bacteria. The aim of this study was to test antimicrobial metals and metal-based nanoparticles efficacy against three viruses, namely influenza A virus (H1N1; A/WSN/1933) and coronaviruses TGEV and SARS-CoV-2; and two bacteria, Escherichia coli and Staphylococcus aureus. The efficacy of ZnO, CuO, and Ag NPs and their respective metal salts, i.e., ZnSO4, CuSO4, and AgNO3, was evaluated in suspensions, and the compounds with the highest antiviral efficacy were chosen for incorporation into fibers of cellulose acetate (CA), using electrospinning to produce filter materials for face masks. Among the tested compounds, CuSO4 demonstrated the highest efficacy against influenza A virus and SARS-CoV-2 (1 h IC50 1.395 mg/L and 0.45 mg/L, respectively), followed by Zn salt and Ag salt. Therefore, Cu compounds were selected for incorporation into CA fibers to produce antiviral and antibacterial filter materials for face masks. CA fibers comprising CuSO4 decreased SARS-CoV-2 titer by 0.38 logarithms and influenza A virus titer by 1.08 logarithms after 5 min of contact; after 1 h of contact, SARS-CoV-2 virus was completely inactivated. Developed CuO- and CuSO4-based filter materials also efficiently inactivated the bacteria Escherichia coli and Staphylococcus aureus. The metal NPs and respective metal salts were potent antibacterial and antiviral compounds that were successfully incorporated into the filter materials of face masks. New antibacterial and antiviral materials developed and characterized in this study are crucial in the context of the ongoing SARS-CoV-2 pandemic and beyond.

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The corona discharge radical injection system for treatment of NOx and SO' has been investigated and demonstrated to improve significantly removal efficiency, energy efficiency, by-products yield etc. In the corona discharge radical injection technique, corona d i s charge is generated in front of a hollow electrode where ammonia, hydrocarbon, steam, oxygen, nitrogen, etc., were injected. Therefore, we can select radicals required for pollution gas treatments and minimize activations of unwanted flue gas components Ill. One of the mechanism of the corona radical shower system is that adiabatic expansion of NHJ contained gas to form core aerosol particles from homogeneous condensation from nozzle exits. Aerosol surface reaction rates are a few orders of magnitude higher than that of the gas phase reaction rates. The other mechanism of NOx and SO2 removal is formation of N (P), N (D), H, Nz*, NH and NHz radicals at the exit of nozzle electrode where strong electric field and high density plasma exist for promote oxidation and reduction reactions. In this work, the mechanism of NOx and SO1 convertion to aerosol particles at downstream of reactors, reacting with slip NH3, and core aerosol particles generated by homogeneous condensation and ion induced aerosol formations will be investigated in detail [21. Experiments were conducted for the flue gas rate from 3 to 12 Nm3/h, the NH3 t o acid gas molecule ratio from 0.5 to 1.5, applied voltage from 0 to 27 kV and SO1 initial concentration from 500 to 1000 ppm. The results show that SO1 removal efficiency increases with increasing ammonia radical injection rate and in-put electrical power. We observed slip NHJ increases with increasing mole ratio and decreases with increasing applied voltage. However, SO2 removal efficiency decreases with increasing mole ratio without discharge. Also, results show that the formation of aerosol particles as well as the particle size distribution depends on applied voltage and initial concentration of SO2.

disinfection methods are urgently required to address global challenges related to energy and water scarcity. [1] Two million people, mostly children, die each year from diarrheal diseases that can be linked to poor sanitation. By 2025, twothirds of the world's population may face water shortages, leading to major flow on effects on a huge range of ecosystems. [2] Chlorination is the most widely used approach for water disinfection, due to its simplicity and easy to administer to water supplies. Despite the ubiquitous nature of chlorine-based disinfection, the formation of disinfection by-products such as trihalomethanes is problematic. [3] Further, chlorine disinfection has been recently shown to naturally accelerate gene exchange in or between bacterial genera, potentially leading to an increased risk of antibiotic resistant bacteria in water, and posing a potential risk to public health. [4] Thus, alternative approaches to wide-ranging and cheap water disinfection are required. These new approaches need Water disinfection is a crucial challenge for humanity. Approaches that are effective, cheap, environmentally friendly, and do not promote gene exchange between bacteria are urgently required. Strongly oxidizing radicals are highly promising to achieve this as they lead to bacterial activation at high efficiencies. However, sources to consistently generate these radicals are limited to high energy UV/H 2 O 2 treatments requiring a large energy input. Here the use of abundant, cheap, brownmillerite (Ca 2 Fe 2 O 5 ) is demonstrated as an efficient radical generation material under dark conditions, showing a seven order of magnitude decrease in bacterial concentration over 10 min. This decrease is attributed to the release of interlayer Ca 2+ from the layered structure of Ca 2 Fe 2 O 5 and hydroxyl radical generation. The efficacy of Ca 2 Fe 2 O 5 is demonstrated by disinfecting turbid sewage sludge. The identification of this cheap, abundant, and nontoxic antibacterial material will provide an opportunity for broad scale clean water generation globally, and address the United Nations' Sustainable Development Goal of clean water and sanitation.

2 A. V,Luikov Heat and Mass Tmnsfer Institute Nationd Academy of Sciences of Belarus 15 P. Brovka Str., Minsk, 220072, Republic of BelarusInteraction between non-thermal Plasmas and flames has been experimentally investigated. Diffusion flames and dielectric barrier discharges (DBD) with a wire-cylinder type were considered. A burner consisted of round type fuel nozzle andIn this study, a new plasma system is introduced to genconcentric coflow confinement. Since the burner was used as eration of rich gas for diesel aftertreatment and other applia plasma reactor at the same time, it was made of quartz cations. tube. Along the centerline of the burner, stainless steel wireThe designed plasma,system allows to reform diesel fuel of 1 mm diameter was protruded as a high voltage electrode. into hydrogen rich gas (Hz + CO). Plasma boosts par-Firstly, the effects of flames on electric dscharges were in-tial oxidation reaction that reforms hydrocarbon fuels into vestigated in terms of discharge onset voltages and delivered hydrogen-rich gas partial oxidation (at. oxygen/carbon ratio powers to the reactor. As results, vigorous streamers were oh-= 1, exothermic reaction): served along with a flame owing to the elevated temperature. As a gas temperature increases gas density decreases simul-CnHm + n/2 0 2 = n CO + m/2 Hz -(10-15)% of energy taneously, which resulted in an increasing reduced electrical released. field (=E/n). The seeding of free electrons and ions generated by the flame also could affect to the enhanced plasma condi-Of non-equilibrium Plasma was used low curtions. k O n d l y , the effects of on flame behaviors rent a plismatron with convective cooling of electrodes. The were investigated. Flame lengths were significantly shortened Power Of a Plasma generator were Used: DC Power as the applied voltage increased owing to the effect of intense suPPIY (looo v, 1000 w, and Pulse generator (15000 kV, 1000 mixing by the ionic wind and the electrically induced flow w). Were gauged temperature of gas in a zone of dixhW% of soot. The yellow luminosity of a diffusion flame from the consumed power and structure of products of reforming. radation of soot were also significantly reduced with increas-The outcomes of experiments allow to h a w a conclusion ing applied -voltages, which can be resulted from the reduc-ahout high performance of a designed plasma system. Potention of soot or decreasing flame temperature. T~ the tial exhaust aftertreatment applications: NO, absorber catdominant mechanism, we measured the temperature of burnt alyst regeneration, HC SCR aftertreatment, operation of DE gases, the concentration of major species, and the spatial dis-on air-fuel mixture with hydrogen admixture. tribution of OH radical, PAH (Poly-Aromatic Hydrocarbons), and soot. Flame temperatures and the concentration of major species measured by thermocouple and ETIR (Fourier Transform Infrared Spectrometer), respectively, were not changed with the plasma generation, which demonstrates that overall chemistries of combustion are not a...